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Abstract:

The present invention relates to a sizing or coating composition that,
when applied to paper substrate, creates a substrate having improved
waterfastness, surface strength, and surface strength as measured by
resistance to abrasion. In addition, the present invention relates to
paper substrates containing the composition, as well as methods of using
and making the paper substrate and composition.

Claims:

1) A sizing or coating composition, comprising at least one binder; at
least one dye fixative; and at least one crosslinking agent.

2) sizing or coating composition according to claim 1, further comprising
at least one pigment.)

3.) The sizing or coating composition according to claim 1, further
comprising at least one inorganic salt.)

4.) The composition according to claim 1, wherein the at least one binder
is present at an amount ranging from 85 to 98 wt % based upon the total
weight of the solids in of the composition.)

5.) The composition according to claim 1, wherein the at least one dye
fixative is present at an amount ranging from 0.5 to 10 wt % based upon
the total weight of the starch in of the composition.)

6.) The composition according to claim 1, wherein the at least one
crosslinking agent is present at an amount ranging from 0.5 to 5 wt %
based upon the total weight of the starch in of the composition.)

7.) The composition according to claim 1, wherein the at least one binder
is at least one member selected from the group consisting of starch,
modified starch and polyvinyl alcohol.

8.) The composition according to claim 1, wherein the at least one dye
fixative is at least one member selected from the group consisting of a
polyamine, a polyeneimine, and an optical brightening
agent:nitrogen-containing compound complex.)

9.) The composition according to claim 1, wherein the at least one
crosslinking agent is at least one member selected from the group
consisting of glyoxal and blocked glyoxal.)

10.) The composition according to claim 1, comprising the at least one
binder at an amount of 85 to 98 wt % based upon the total weight of the
solids in of the composition; at least dye fixative at an amount ranging
from 0.5 to 10 wt % based upon the total weight of the starch in of the
composition; and at least one crosslinking agent at an amount ranging
from 0.25 to 5 wt % based upon the total weight of the starch in of the
composition.

11.) The composition according to claim 10, wherein the at least one
binder is selected from the group consisting of starch and polyvinyl
alcohol; the at least one dye fixative is selected from the group
consisting of a polyamine, a polyeneimine, and an optical brightening
agent:nitrogen-containing compound complex; and the at least one
crosslinking agent is selected from the group consisting of glyoxal and
blocked glyoxal.)

12. A paper substrate, comprising the composition according to claim 11.

13. The paper substate according to claim 12, comprising an effective
amount of the composition such that the substrate has a waterfastness as
measured by DL % of from -10 to 15.

14.) The paper substate according to claim 12, comprising an effective
amount of the composition such that the substrate has a waterfastness as
measured by DL % is from 5 to 55.

15.) The paper substrate according to claim 12, comprising an effective
amount of the composition such that the substrate has a surface strength
that is less than 60 mg/1000 revolutions as measured by the Taber
Abrasion test.)

16.) The paper substrate according to claim 12, comprising an effective
amount of the composition such that the substrate has a surface strength
that is less than 50 mg/1000 revolutions as measured by the Taber
Abrasion test.)

17.) The paper substrate according to claim 12, comprising an effective
amount of the composition such that the substrate has a surface strength
that is less than 40 mg/1000 revolutions as measured by the Taber
Abrasion test.)

18.) The paper substrate according to claim 12, comprising an effective
amount of the composition such that the substrate; when in a roll that is
36 inches wide, 50 inches in diameter, and having a 3 inch core, runs
continuously for greater than half of a total length of the roll.)

19.) The paper substrate according to claim 12, comprising an effective
amount of the composition such that the substrate; when in a roll that is
36 inches wide, 50 inches in diameter, and having a 3 inch core, runs
continuously for at least two lengths of the roll.)

20.) A method of making the paper substrate according to claim 12,
comprising contacting a web of fibers with the composition at a size
press or at a coater.

Description:

[0001] The present application claims the benefit of priority under 35 USC
§119(e) to U.S. Provisional Patent Application 60/931,163, filed May
21, 2007, which is hereby incorporated, in its entirety, herein by
reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a sizing or coating composition
that, when applied to paper substrate, creates a substrate having
improved waterfastness, surface strength, and surface strength as
measured by resistance to abrasion. In addition, the present invention
relates to paper substrates containing the composition, as well as
methods of using and making the paper substrate and composition. In
particular, the substrate may be printed via inkjet printing
methodologies (including dye and pigment inks) and/or may be printed via
inkjet and offset printing methodologies (e.g. a dual use paper is
possible in some instances).

[0006] However, conventional paper substrates such as those above remain
poor in balancing waterfastness, surface strength and runnability,
especially if used as a dual purpose sheet for both offset and inkjet
(dye and/or pigment-based) recording. Accordingly, there is a need to
provide such high-performance and functionality to paper substrates.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1: A first schematic cross section of just one exemplified
embodiment of the paper substrate that is included in the paper substrate
of the present invention.

[0008] FIG. 2: A second schematic cross section of just one exemplified
embodiment of the paper substrate that is included in the paper substrate
of the present invention.

[0009] FIG. 3: A third schematic cross section of just one exemplified
embodiment of the paper substrate that is included in the paper substrate
of the present invention.

[0011] FIG. 5: A bar graph demonstrating that the present invention has
improved surface strength as measured by abrasion resistance.

DETAILED DESCRIPTION OF THE INVENTION

[0012] The present inventors have discovered a composition that, when
applied to a web of cellulosic fibers, creates a paper substrate having
improved waterfastness, surface strength and runnability. This substrate
may be used with inkjet printing (dye or ink-based) alone, or may be used
as a dual purpose sheet for both offset and inkjet (dye and/or
pigment-based) recording. Thus the substrate of the present invention may
be used as a recording sheet for inket printing alone or for dual purpose
offset/inkjet printing.

[0013] The composition may contain a solvent such as water and at least
one binder. Examples of binders include, but are not limited to starch,
polyvinyl alcohol, polyvinylamine, alginate, carboxymethyl cellulose.
Examples of starches include, for example, oxidized, cationic, ethylated,
hydroethoxylated, etc. Further, the starch may be of any type, including
but not limited to oxidized, ethylated, cationic and pearl, and is
preferably used in aqueous solution. illustrative of useful starches for
the practice of this preferred embodiment of the invention are naturally
occurring carbohydrates synthesized in corn, tapioca, potato and other
plants by polymerization of dextrose units. All such starches and
modified forms thereof such as starch acetates, starch esters, starch
ethers, starch phosphates, starch xanthates, anionic starches, cationic
starches and the like which can be derived by reacting the starch with a
suitable chemical or enzymatic reagent can be used in the practice of
this invention.

[0014] Useful starches may be prepared by known techniques or obtained
from commercial sources. For example, the suitable starches include
PG-280 from Penford Products, SLS-280 from St. Lawrence Starch, the
cationic starch CatoSize 270 from National Starch and the hydroxypropyl
No. 02382 from Poly Sciences, Inc.: CatoSize 270 and KoFilm 280 (all from
National Starch) and PG-280 ethylated starches and AP Pearl starches.

[0015] When polyvinyl alcohol is utilized, polyvinyl alcohol (PVOH) may be
produced by hydrolyzing polyvinyl acetate (PVA). The acetate groups are
replaced with alcohol groups and the higher the hydrolysis indicates that
more acetate groups have been replaced. Lower hydrolysis/molecular weight
PVOH are less viscous and more water soluble. While the PVOH may have any
% hydrolysis, the PVOH may have, for example, a % hydrolysis ranging from
100% to 75%.

[0016] The composition may contain any amount of binder, including from 70
wt % to 99 wt %, from 80 wt % to 98 wt %, and from 85 wt % to 96 wt %,
based upon the total weight of the solids in the composition. The
composition may contain 70, 75, 78, 80, 82, 84, 85, 86, 88, 90, 92, 94,
95, 96, 97, 98 and 99 wt % of the binder based upon the total weight of
the solids in the composition, including any and all ranges and subrange
therein.

[0017] The composition may also contain at least one dye fixative.
Examples of dye fixatives include nitrogen containing compounds. The
nitrogen containing compound may be inorganic or organic, preferably
organic. Suitable nitrogen containing compounds, oligomers and polymers
are those containing one or more quaternary ammonium functional groups.
Such functional groups may vary widely and include substituted and
unsubstituted amines, imines, amides, urethanes, quaternary ammonium
groups, dicyandiamides and the like. Illustrative of such materials are
polyamines, polyethyleneimines, copolymers of diallyldimethyl ammonium
chloride (DADMAC), copolymers of vinyl pyrrolidone (VP) with quaternized
diethylaminoethylmethacrylate (DEAMEMA), polyamides, cationic
polyurethane latex, cationic polyvinyl alcohol, polyalkylamines
dicyandiamid copolymers, amine glycigyl addition polymers,
polyoxyethylene (dimethyliminio) ethylene (dimethyliminio) ethylene]
dichlorides, and polyguanides such as poly(hexamethylene biguanide).
While the nitrogen containing compound may have any molecular weight, the
molecular weight may be equal to or less than 100,000 daltons, preferably
equal to or less than about 50,000 and more preferably less than about
10,000. The molecular weight may be 100, 200, 500, 1000, 2000, 3000,
5000, 10000, 250000, 50000, and 100000, including any and all ranges and
subranges therein. Illustrative of such materials are polyalkylamine
dicyandiamide copolymers, poly [oxyethylene(dimethyliminio
ethylene(dimethyliminioethylend dichlorides and polyamines. Other
examples include low molecular weight cationic polymers such as
polyalkylamine dicyandiamid copolymer, poly[oxyethylene
(dimethyliminio)ethylene(dimethyliminio)ethy lend] dichloride. Still
further, the nitrogen containing compounds include low molecular weight
polyalkylamine dicyandiamid copolymers. Examples of modified poly(vinyl
alcohol)-co-poly(vinyl amine) polymers with cationic functional groups
attached thereto are also useful nitrogen containing species, such as
those found in US published patent application US2005/0020729 and PCT
application WO2003054030, which are both hereby incorporated in their
entirety by reference. Examples of cationic latex polymers that are
included as nitrogen containing species are those found in US published
patent application US2005/0020729, which is hereby incorporated in its
entirety by reference. Further examples of dye fixatives are those found
in U.S. Pat. No. 6,764,726, which is hereby incorporated in its entirety
by reference, as well as those commercially available as Bubond 60 from
Buckman that has a molecular weight of 2,000 Daltons.

[0018] In one embodiment, the dye fixative may be used in combination with
an optical brightening agents, such as for example in a complex. Such
complexes may, for example, be formed via covalently bonding the dye
fixative to the optical brightening agent. Optical brightening agents
("OBAs") used in the practice of the process of this invention may vary
widely and any conventional OBA used or which can be used to brighten
mechanical or Kraft pulp can be used in the combination with the dye
fixative. Optical brighteners are dye-like fluorescent compounds which
absorb the short-wave ultraviolet light not visible to the human eye and
emit it as longer-wave blue light, with the result that the human eye
perceives a higher degree of whiteness and the degree of whiteness is
thus increased. This provides added brightness and can offset the natural
yellow cast of a substrate such as paper. Optical brighteners used in the
present invention may vary widely and any suitable optical brightener may
be used. An overview of such brighteners is to be found, for example, in
Ullmann's Encyclopedia of Industrial Chemistry, Sixth Edition, 2000
Electronic Release, OPTICAL BRIGHTENERS--Chemistry of Technical Products
which is hereby incorporated, in its entirety, herein by reference. Other
optical brighteners are described in U.S. Pat. Nos. 5,902,454; 6,723,846;
6,890,454; 5,482,514; 6,893,473; 6,723,846; 6,890,454; 6,426,382;
4.169,810; and 5,902,454 and references cited therein which are all
incorporated by reference. Still other optical brighteners are described
in U.S. Pat. Application Publication Nos. US 2007/0193707; US 2004/014910
and US 2003/0013628; and WO 96/00221 and of which are hereby
incorporated, in their entirety, herein by reference. Illustrative of
useful optical brighteners are
4,4'-bis-(triazinylamino)-stilbene-2,2'-disulfonic acids,
4,4'-bis-(triazol-2-yl)stilbene-2,2'-disulfonic acids,
4,4'-dibenzofuranyl-biphenyls, 4,4'-(diphenyl)-stilbenes,
4,4'-distyryl-biphenyls, 4-phenyl-4'-benzoxazolyl-stilbenes,
stilbenyl-naphthotriazoles, 4-styryl-stilbenes, bis-(benzoxazol-2-yl)
derivatives, bis-(benzimidazol-2-yl) derivatives, coumarins, pyrazolines,
naphthalimides, triazinyl-pyrenes, 2-styryl-benzoxazole or
-naphthoxazoles, benzimidazole-benzofurans or oxanilides.

[0019] Most commercially available optical brightening agents are based on
stilbene, coumarin and pyrazoline chemistries and these are preferred for
use in the practice of this invention. More preferred optical brighteners
for use in the practice of this invention are optical brighteners
typically used in the paper industry based on stilbene chemistry such as
1,3,5-triazinyl derivatives of 4,4'-diaminostilbene-2,2'-disulfonic acid
and salts thereof, which may carry additional sulfo groups, as for
example at the 2, 4 and/or 6 positions. Stilbene derivatives as for
example those commercially available from Ciba Geigy under the tradename
"Tinopal", from Clariant under the tradename "Leucophor", from Lanxess
under the tradename "Blankophor" , and from 3V under the tradename
"Optiblanc" such as disulfonate, tetrasulfonate and hexasulfonate
stilbene based optical brightening agents. Of course, if the dye fixative
is covalently attached to OBAs having similar chemistries as those
mentioned above, the OBA chemistry may change from anionic to cationic in
nature, such as a cationic stilbene-based OBA. An example of a dye
fixative that is in the form of a complex with an OBA or that may also
act as an OBA is that which is commercially available from Clariant as
Leucophor FTS. Further examples of such dye fixative/OBA dual function
compounds and/or formulations include those when the OBA is cationic
rather than anionic. Still further, examples can be found in U.S. Pat.
Nos. 7,060,201 and 6,890,454, which is hereby incorporated, in its
entirety, herein by reference.

[0020] The composition may contain any amount of the nitrogen containing
compound, including from 0.01 to 10 wt %, from 0.1 to 7 wt %, from 0.5 to
6 wt %, and from 1 wt % to 6 wt %, based upon the total dry weight of the
starch in the composition. The composition may contain 0.01, 0.05, 0.1,
0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 6.0, 7.0, 8.0, 9.0, and
10.0 wt % of the binder based upon the total dry weight of the starch in
the composition, including any and all ranges and subrange therein.

[0021] The composition may also contain a crosslinking agent. The
crosslinking agent may be any chemical that is capable of crosslinking
the hydroxyl groups of starch and/or the functional groups of the dye
fixative. The crosslinking agent may be formaldehyde, urea,
formaldehyde/urea resins, melamine, formaldehyde/melamine resins, acid
anhydrides, maleic anhydride, anhydrides, metal salts, boron-containing
compounds, boron containing salts, metal containing boron compounds,
borates, sodium borate, ammonium salts, zirconium salts, AZT, glyoxal,
blocked glyoxal such as those commercially available from Clariant (known
as Cartbond TSI). Examples of blocked glyoxals are those that have the
reactive groups either sterically or chemically blocked so that such
groups may not react until a temperature of the compound is reached.
While this temperature could be any temperature, in some circumstances
the temperature could be greater than 150° Farenheit or even at
least 160° Farenheit.

[0022] The composition may contain any amount of the nitrogen containing
compound, including from 0.01 to 7 wt %, from 0.1 to 5 wt %, from greater
than 0.5 to 4 wt %, and from 1 wt % to 3 wt %, based upon the total dry
weight of the starch in the composition. The composition may contain
0.01, 0.05, 0.1, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5.4.0, 4.5, 5.0, 6.0,
7.0, 8.0, 9.0, and 10.0 wt % of the binder based upon the total dry
weight of the starch in the composition, including any and all ranges and
subrange therein.

[0023] The composition may optionally contain at least one inorganic salt.
Suitable inorganic salts may be monovalent and/or divalent and/or
trivalent and may contain any level of hydration complexes thereof.
Exemplified inorganic salts are those from Groups 1, 2 and 13 from the
Periodic Table of Elements and hydrated complexes thereof, including
monohydrates, dihydrates, trihydrates, tetrahydrates, etc. The cation of
the salt may be sodium, calcium, magnesium, and aluminum preferably. The
anionic counterion to the cation of the inorganic salt may be any
counterion. Examples of the counterion include organic counterions,
phosphate, sulfates, and halogens such as chloride, boride, fluoride, etc
and/or hydroxyl group(s). The most preferred inorganic salts being sodium
chloride and/or calcium chloride. When the inorganic salt is optionally
present, it may be present at any amount, including from 1 to 50 wt % and
from 8 to 37 wt %, based upon the total dry weight of the starch. The
inorganic salt may be 1, 5, 8, 10, 15, 20, 25, 30, 35, 36, 37, 38, 39,
40, 42, 45, 47, and 50 wt %, including any and all ranges and subranges
therein.

[0024] Further optional components that may be present in the composition
include pigment, dispersants, fluorescent dyes, surfactants, defaming
agents, preservatives, pigments, binders, pH control agents, coating
releasing agents, and the like.

[0025] The composition may be contacted with a web of cellulosic fibers to
make a paper substrate of the present invention. The fibers may be
synthetic. Examples of synthetic fibers may be those made from polyolefin
fibers. Such synthetic fibers are commercially available as for example
from DuPont under the trademark "Tyvex". The fibers may be recycled
fibers and/or virgin fibers. Recycled fibers differ from virgin fibers in
that the fibers have gone through the drying process at least once. The
sources of the fibers are from softwood and/or hardwood. Further, the
softwood and/or hardwood fibers contained by the paper substrate of the
present invention may be modified by physical and/or chemical means.
Examples of physical means include, but is not limited to,
electromagnetic and mechanical means. Means for electrical modification
include, but are not limited to, means involving contacting the fibers
with an electromagnetic energy source such as light and/or electrical
current. Means for mechanical modification include, but are not limited
to, means involving contacting an inanimate object with the fibers.
Examples of such inanimate objects include those with sharp and/or dull
edges. Such means also involve, for example, cutting, kneading, pounding,
impaling, etc means. Examples of chemical means include, but is not
limited to, conventional chemical fiber modification means. Examples of
such modification of fibers may be, but is not limited to, those found in
the following U.S. Pat. Nos. 6,592,717, 6,582,557, 6,579,415, 6,579,414,
6,506,282, 6,471,824, 6,361,651, 6,146,494, H1,704, 5,698,688, 5,698,074,
5,667,637, 5,662,773. 5,531,728, 5,443,899, 5,360,420, 5,266,250,
5,209,953, 5,160,789, 5,049,235, 4,986,882, 4,496,427, 4,431,481,
4,174,417, 4,166,894, 4,075,136, and 4,022,965, which are hereby
incorporated in their entirety by reference.

[0026] The substrate of the present invention contains an effective amount
of the above-described composition and/or components within the
composition. An effective amount of the composition and/or components
within the composition may be applied to the web of cellulosic fibers. An
effective amount is meant to be the amount necessary to achieve a good
balance of waterfastness, surface strength, and runnability as described
below.

[0027] Although the effective amount of the composition could be any
amount to obtain any one or more of the below-described performance
and/or physical characteristics of the substrate, it is preferable that
an effective amount of the composition is added such that the paper
substrate contains from 50 to 150 lbs of starch per ton of web. The
amount of starch may be 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, and
150 lbs/ton of paper, including any and all ranges and subranges therein.
In addition, it is preferably that an effective amount of the composition
is added such that the paper substrate contains from 0.1 to 15 lbs of dye
fixative per ton of web. The amount of dye fixative may be 0.1, 0.2, 0.5,
1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
and 15 lbs/ton of web, including any and all ranges and subranges
therein. In addition, it is preferably that an effective amount of the
composition is added such that the paper substrate contains from 0.01 to
15 lbs of crosslinker per ton of web. The amount of crosslinker may be
0.01, 0.02, 0.05, 0.08, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0,
1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.2, 2.5, 2.8, 3.0,
3.2, 3.5, 4.0, 4.5, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and 15 lbs/ton of
web, including any and all ranges and subranges therein.

[0028] The substrate may have one or more improved properties that enhance
the image waterfastness of recording sheets formed from the substrate.
Although there are many ways to measure waterfastness, we describe the
waterfastness test referred to within this document hereinbelow. It
should be noted that the test described below is very similar to ASTM
test F2292-03, which is hereby incorporated in its entirety by reference.
Of course, any differences will be noted.

[0029] If a solid color is printed on a sheet or paper and the printed
section is immersed into water, some ink will dissolve into the water
leaving the remaining image faded or less dark. The density (darkness) of
the printed solid can be measured with an optical densitomer both before
and after immersion into water. The difference between the density
readings can be expressed as the density loss ("DL %"). The method
involves printing solid colored stripes on paper, immersing one-half of
the stripe into deionized water at 23° C. for 60 seconds, and then
air drying the paper. The optical density is read on the immersed
(ODW) and non-immersed (ODO) portions of the stripe by a
reflectance densitometer (X-Rite, Macbeth. Etc.). The percent density
loss ("DL %") is defined as DL %=[(ODW-ODO/ODO]×100.
In this equation, a positive DL % indicates a density increase after
water immersion. While we do not wish to be bound by any theory, it is
believed that this density increase is done to ink dye redistribution
which provides for a more uniform ink coverage. A negative DL % is
believed to indicate that the ink dye is washed out after the sample is
subjected to water immersion and is undesirable. Preferably, the DL % is
from about -10% to about 15%. More preferably, the DL % is from about -5%
to about 15%. Most preferably, the DL % is from about 0% to about 15%.
The DL % may be -10, -7, -5, -3, 0, 3, 5, 7, 10, 12, and 15%, including
any and all ranges and subranges therein.

[0030] The substrate may have enhanced the surface strength. An example of
enhanced surface strength is enhanced resistance to abrasion as measured
by Taber Abrasion according to standard Tappi Test T 476 om-06, which is
hereby incorporated in its entirety by reference. The Taber Abrasion may
be any amount, including less than about 75, less than about 60, less
than 50, and less than 40 mg/1000 revolutions. The Taber Abrasion may be
less than about 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20 15, 10,
and 5 mg/1000 revolutions, including any and all ranges and subranges
therein.

[0031] The substrate may have enhanced runnability. An example of enhanced
runnability is exemplified by testing to see how many standard rolls of
substrate (standard rolls are 36 inches wide, 50 inches in diameter, and
having a 3 inch core) may be printed with the offset press mentioned
below using the chemicals and conditions mentioned below:

[0033] The Test is to see how many standard rolls will run through the
press before the offset printer plates must be replaced or cleaned due to
contamination thereof and/or deposits from substrate attached thereto the
plates. Using this test, the substrate of the present invention, when
placed in standard rolls, may run for greater than half of a standard
roll, preferably greater than one standard roll, more preferably at least
two standard rolls, and most preferably at least three standard rolls
before offset printer plates must be replaced or cleaned due to
contamination thereof arid/or deposits from substrate attached thereto
the plates. Conventional substrates, when tested according to the above,
are not capable of running for greater than a half of a standard roll,
and usually greater than 1 roll before offset printer plates must be
replaced or cleaned due to contamination thereof and/or deposits from
substrate attached thereto the plates.

[0034] The paper substrate of the present invention may have any black
optical print density as measured by TAPPI METHOD T 1213 sp-03. The black
optical density may be from 0.8 to 2.0, more preferably from 1.9 to 1.5.
The black optical density may be 0.8, 0.9, 1.0, 1.05, 1.06, 1.07, 1.08,
1.09, 1.10, 1.11, 1.12, 1.13, 1.14, 1.15, 1.16, 1.17, 1.18, 1.19, 1.2,
1.3, 1.4, and 1.5, including any and all ranges and subranges therein.

[0035] The Hercules Sizing Test Value ("HST") of the substrate may be any
HST. The HST is measured using the procedure of TAPPI 530 pm-89. In the
preferred embodiments of this invention, the HST is preferably from about
1 second to about 400 seconds, including from 1 to 200 seconds, less than
100 seconds, less than 50 seconds, and less than 10 seconds. The HST may
be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 25, 30, 35, 40,
45, 50, 60, 70, 80, 90, 100, 125, 150, 175, 200, 225, 250, 275, 300, 325,
350, 375, and 400 seconds, including any and all ranges and subranges
therein.

[0036] The substrate can be of any basis weight, including from 10 to 40
lbs/1300 ft2, 15 to 30 lbs/1300 ft2, 18-28 lbs/1300 ft2,
and about 20 and 24 lbs/1300 ft2. The basis weight may be 10, 15,
18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30. 35, and 40 lbs/1300
ft2, including any and all ranges and subranges therein.

[0037] The substrate can be of any density, including from 0.5 to 1.0,
from 0.6 to 0.9, from 0.65 to 0.85, and from 0.7 to 0.8 g/cm3. The
densisty may be 0.5, 0.55, 0.6, 0.65, 0.7, 0.72, 0.74, 0.75, 0.76, 0.78,
0.8, 0.85, 0,9, 0.95 and 1.0 g/cm3, including any and all ranges and
subranges therein.

[0038] This composition of the present invention may be added internally
or to a surface of the web of cellulosic fibers to make the substrate of
the present invention. Surface application is preferable. Examples of
surface applications a size press and/or coater. The size press may be
any size press commonly known in the art. For example, the size press may
be a puddle mode size press (e.g. inclined, vertical, horizontal) or
metered size press (e.g. blade metered, rod metered), etc. The coater may
be any coater commonly known in the art. For example, the coater may be a
blade coater or air knife coater, a bar coater, Meyer rod coater, reverse
roll coater, extrusion coater, a gravure or reverse-gravure coater, a
curtain coater, a dip coater, and a spray coater, etc.

[0039] FIGS. 1-3 demonstrate different embodiments of the paper substrate
1 in the paper substrate of the present invention. FIG. 1 demonstrates a
paper substrate 1 that has a web of cellulose fibers 3 and a composition
2 where the composition 2 has minimal interpenetration of the web of
cellulose fibers 3. Such an embodiment may be made, for example, when a
composition is coated onto a web of cellulose fibers.

[0040] FIG. 2 demonstrates a paper substrate 1 that has a web of cellulose
fibers 3 and a composition 2 where the composition 2 interpenetrates the
web of cellulose fibers 3. The interpenetration layer 4 of the paper
substrate 1 defines a region in which at least the composition penetrates
into and is among the cellulose fibers. The interpenetration layer may be
from 1 to 99% of the entire cross section of at least a portion of the
paper substrate, including 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50,
55, 60, 65, 70, 75, 80, 85, 90, 95, and 99% of the paper substrate,
including any and all ranges and subranges therein. Such an embodiment
may be made, for example, when a composition is added to the cellulose
fibers prior to a coating method and may be combined with a subsequent
coating method if required. Addition points may be at the size press, for
example.

[0041] FIG. 3 demonstrates a paper substrate 1 that has a web of cellulose
fibers 3 and a solution 2 where the composition 2 is approximately evenly
distributed throughout the web of cellulose fibers 3. Such an embodiment
may be made, for example, when a composition is added to the cellulose
fibers prior to a coating method and may be combined with a subsequent
coating method if required. Exemplified addition points may be at the wet
end of the paper making process, the thin stock, and the thick stock.

[0042] The paper substrate may be made by contacting any component of the
composition with the cellulose fibers consecutively and/or
simultaneously. Still further, the contacting may occur at acceptable
concentration levels that provide the paper substrate of the present
invention to contain any of the above-mentioned amounts of cellulose and
components of the sizing solution. The contacting may occur anytime in
the papermaking process including, but not limited to the thick stock,
thin stock, head box, size press and coater. Further addition points
include machine chest, stuff box, and suction of the fan pump.
Preferably, the components of the composition are preformulated either
together and/or in combination within a single and/or separate coating
layer(s) and coated onto the fibrous web via a size press and/or coater.

[0043] When the composition is applied to the web of cellulosic fibers,
especially at a size press, the amount of composition applied thereto may
be from 1 to 300 dry lbs/ton of web, including from 50 to 150, from 75 to
125, and from 80 to 100 dry lbs/ton of web. The amount of composition
that is applied to the web may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20,
25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90 , 95, 100, 110,
120, 125, 130, 140, 150, 160, 170, 180, 190, 200, 225, 250, 275, and 300
dry lbs/ton of web, including any and all ranges and subranges therein.

[0044] In one embodiment, the binder may be applied via a size press at
typical sizing amounts to create a sized web. Then, a coater may apply a
composition containing the dye fixative and/or the crosslinking agent at
the same time or sequentially. In this case, the coater may place any
amount of dye fixative and/or crosslinking agent to the sized web,
including from 0.25 to 25, 0.5 to 10, and 1.5 to 5 dry lbs/ton of web. In
this embodiment, the amount of dye fixative and/or crosslinking agent
applied to the web may be 0.25, 0.5, 0.75, 1.0, 1.25, 1.5, 1.75, 2.0,
2.25, 2.5, 2.75, 3.0, 3.25, 3.5, 3.75, 4.0, 4.25, 4.5, 4.75, 5, 6, 7, 8,
9, 10, 12, 15, 20 and 25 dry lbs/ton of web, including any and all ranges
and subranges therein.

[0045] The paper or paperboard of this invention can be prepared using
known conventional techniques. Methods and apparatuses for forming and
making and applying a coating formulation to a paper substrate are well
known in the paper and paperboard art. See for example, G. A. Smook
referenced above and references cited therein all of which is hereby
incorporated by reference. All such known methods can be used in the
practice of this invention and will not be described in detail.

[0046] The essential one or more nitrogen containing organic species and
one or more starches and optional components can be dissolved or
dispersed in an appropriate liquid medium, preferably water, and can be
applied to the substrate by any suitable technique.

[0047] Paper substrates of the present invention can be employed in ink
jet printing processes. One embodiment of the present invention is
directed to a process which comprises applying an aqueous recording
liquid to a recording sheet of the present invention in an image wise
pattern. Another embodiment of the present invention is directed to a
printing process which comprises (1) incorporating into an ink jet
printing apparatus containing an aqueous ink a recording sheet of the
present invention, and (2) causing droplets of the ink (dye and/or
pigment-based) to be ejected in an image wise pattern onto the recording
sheet, thereby generating images on the recording sheet. Ink jet printing
processes are well known, and are described in, for example, U.S. Pat.
No. 4,601,777, U.S. Pat. No. 4,251,824, U.S. Pat. No. 4,410,899, U.S.
Pat. No. 4,412,224, and U.S. Pat. No. 4,532,530, the disclosures of each
of which are totally incorporated herein by reference. In a particularly
preferred embodiment, the printing apparatus employs a thermal ink jet
process wherein the ink in the nozzles is selectively heated in an
imagewise pattern, thereby causing droplets of the ink to be ejected in
imagewise pattern. The recording sheets of the present invention can also
be used in any other printing or imaging process, such as printing with
pen plotters, imaging with color laser printers or copiers, handwriting
with ink pens, offset printing processes, or the like, provided that the
toner or ink employed to form the image is compatible with the ink
receiving layer of the recording sheet.

[0048] The present invention will be described with references to the
following examples. The examples are intended to be illustrative and the
invention is not limited to the materials, conditions, or process
parameters set forth in the example. All parts and percentages are by
unit weight unless otherwise indicated.

EXAMPLES

Example 1

(A) Preparation of Size Press Compositions

[0049] A series of size press compositions were prepared using the
following procedure. The composition is prepared in the lab using a low
shear mixer. A certain amount of pre-cooked starch is added to the mixing
container, then the Bubond 60 or the Leucophor FTS dye fixatives, then
the crosslinker which is diluted in the remaining water.under proper
shear actions. The desired solids for this application is in a range of
14 to 16% depending on the tolerance of the system to size press
treatment viscosity, and the desired pickup. The compositions and
specifications are set for the in the following Table 1.

[0050] A base paper that was manufactured at Pensacola mill, paper machine
P5, which did not have any size press application and a basis weight of
about 75 g/m2 was used in this study. The HST values was about 1
second, The base paper was coated with the coating compositions of Table
1 using a lab scale puddle size press. To apply the coating formulation,
a 12'' wide roll of paper substrate is continuously fed between two
rollers, and the coating formulation is pumped into the nip reservoir,
the paper being fed through the nip reservoir at a prefixed speed. By
controlling the formulation solids, nip pressure, and size press running
speed, the desired pickup weights mentioned in Table 1 were achieved. The
amounts are provided in units of ?

[0051] The waterfastness and abrasion tests were performed on each of the
above samples of Table I. The results of each test are found in FIGS. 4
and 5, respectively. Print density is measured using a reflectance
densitometer (X-Rite, Macbeth. Etc.) in units of optical density ("OD").
The method involves printing a solid block of color on the sheet, and
measuring the optical density. There is some variation in OD depending on
the particular printer used and the print mode chosen, as well as the
densitometer mode and color setting. The printer used in this patent is a
Scitex 4.5'' wide printhead, which is connected to a microcomputer to
determine the print pattern to print. The paper is attached to a drum
which can spin at various speeds to simulate a printing press operating
at different paper web speeds. The samples in this patent were printed at
an equivalent web speed of 500 ft/min, using #1040 Scitex ink. The
densitometer used was an X-Rite model 528 spectrodensitometer with a 6 mm
aperature. The density measurement settings were Visual color, status T,
and absolute density mode.

[0052] The waterfastness testing was performed by dipping the printed
sample in room temperature water for one minute, and then removing the
sample and allowing the sample to air dry. The print density was measured
before and after dipping, and the % change in print density calculated.
The Taber Wet Abrasion test was performed using the method described in
Tappi standard T476.

[0053] Numerous modifications and variations on the present invention are
possible in light of the above teachings. It is, therefore, to be
understood that within the scope of the accompanying claims, the
invention may be practiced otherwise than as specifically described
herein.

[0054] As used throughout, ranges are used as a short hand for describing
each and every value that is within the range, including all subranges
therein.

[0055] All of the references, as well as their cited references, cited
herein are hereby incorporated by reference with respect to relative
portions related to the subject matter of the present invention and all
of its embodiments